On the Cover

September-October 2000 Volume 88, Number 5

Ideas about the proton have evolved considerably since Rutherford first
identified this subatomic particle in the second decade of the 20th
century. In "The Search for QCD Exotics," Alex R. Dzierba, Curtis A.
Meyer and Eric S. Swanson explain that theorists realized in the 1960s
that the proton contains three elementary subunits—dubbed quarks. ...